High speed and density are two major factors for driving the development of high technologies, not just lowering the production cost only, but most importantly also satisfying consumer requirements, so that electronic products and mobile communication products are tended to be developed with a light, thin, short and compact design, high reliability, and low cost, and these products are developed in a generation of every three to five years. To cope with the trend, electronic components occupying a relatively large area are also having an integrated revolution in the circuit design of the electronic products.
In a printed circuit board, the area occupied by the electronic components is the main limitation to a compact product, and many soldering points are added to the printed circuit board, and thus reducing the system reliability as well as increasing the manufacturing cost. With the requirements of high performance, small volume, and light weight, a larger space is wanted to be created in the substrate area of the printed circuit board with a limited area to enhance the functionality of modules, so that the integration and embedment of electronic components are important development trends.
To overcome the aforementioned issues, the electronic components are embedded traditionally, wherein a plastic carrier board is provided for fixing the electronic components, but this method is restricted to the precision of the SMT insertion machine, and if there is an offset occurred at the position of an electronic component with respect to the insertion machine, then a poor signal transmission will result. Alternatively, a solder paste is provided for fixing the electronic components and carrying out the electrical conduction, but the coefficient of expansion of the solder paste has a relatively large difference from the coefficient of expansion of other components in the printed circuit board, so that when there is a large temperature change, the thermal expansion and contraction of the solder paste gives rise to an unstable quality of the whole printed circuit board, and these are the drawbacks of the prior art.